created physics system and new Drawable interface

src/main/java/core/Drawable.java

@@ -0,0 +1,18 @@
+package core;
+
+import java.awt.*;
+
+public interface Drawable {
+    /**
+     * <p>The draw method is called every frame after the update by the master object on each object. Everything
+     * about drawing should be handled here in this method.</p>
+     * <p>No general calculations should be made in this method. The game should be able to work just
+     * fine even without this method being called.</p>
+     * <p>This function is <i>NOT</i> intended to be called manually.</p>
+     *
+     * @param g2d    The {@code Graphics2D} object given by the master
+     * @param w      The width of the screen
+     * @param master The master object itself
+     */
+    void draw(Graphics2D g2d, int w, Master master);
+}

src/main/java/core/Master.java

@@ -1,6 +1,7 @@
 package core;
 
 import core.math.Vector2D;
+import core.physics.Collidable;
 import objects.DebugPos;
 import objects.ships.BattleShip;
 import objects.GameObject;
@@ -11,6 +12,9 @@ import objects.world.Wall;
 import javax.swing.*;
 import java.awt.*;
 import java.util.ArrayList;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+//TODO master better accessible or something
 
 /**
  * The main object that controls everything
@@ -35,6 +39,16 @@ public class Master extends JPanel {
      */
     private final ArrayList<GameObject> objects;
 
+    /**
+     * All GameObjects that can be drawn
+     */
+    private final ArrayList<Drawable> drawables;
+
+    /**
+     * All physics objects that exist
+     */
+    private final ArrayList<Collidable> collidables;
+
     /**
      * Stores all GameObjects that were created during a frame
      */
@@ -48,8 +62,10 @@ public class Master extends JPanel {
     public Master() {
         objects = new ArrayList<>();
         objectBuffer = new ArrayList<>();
+        collidables = new ArrayList<>();
+        drawables = new ArrayList<>();
 
-        objects.add(new Grid());
+        create(new Grid());
 
 
         BattleShip battleShip = new BattleShip(Color.DARK_GRAY);
@@ -57,15 +73,16 @@ public class Master extends JPanel {
         /*for (int i = 0; i < 10; i++) {
             bs.addTurret(new Turret(bs, 25, 10 * i + 1, 50, i % 5));
         }*/
-        objects.add(bs);
-        objects.add(battleShip);
+        create(bs);
+        create(battleShip);
 
-        objects.add(new Submarine(new Vector2D(), new Vector2D(20, 20)));
-        objects.add(new Wall(20, 80, 50, 2));
+        create(new Submarine(new Vector2D(), new Vector2D(20, 20)));
+        create(new Wall(20, 80, 50, 2));
     }
 
     /**
      * The mein drawing method, handles everything about drawing
+     *
      * @param g
      */
     private void doDrawing(Graphics g) {
@@ -81,7 +98,7 @@ public class Master extends JPanel {
 
         Graphics2D g2d = (Graphics2D) g.create();
 
-        objects.forEach(o -> o.draw(g2d, w, this));
+        drawables.forEach(o -> o.draw(g2d, w, this));
     }
 
 
@@ -93,11 +110,11 @@ public class Master extends JPanel {
 
     /**
      * Debug a position, creates a green dot at the position
+     *
      * @param pos
      */
     public void debugPos(Vector2D pos) {
         create(new DebugPos(pos, new Vector2D(10, 10)));
-        System.out.println(pos);
     }
 
     /**
@@ -120,6 +137,7 @@ public class Master extends JPanel {
 
     /**
      * Get the current location of the mouse relative to the frame
+     *
      * @return The location of the mouse, already normalized
      */
     public Point getMouseLocation() {
@@ -134,9 +152,33 @@ public class Master extends JPanel {
 
     /**
      * This method has to be called for every newly created GameObject
-     * @param obj
+     *
+     * @param obj The new object
      */
     public void create(GameObject obj) {
         objectBuffer.add(obj);
+        if (obj instanceof Collidable) {
+            collidables.add((Collidable) obj);
+        }
+        drawables.add(obj);
+
+    }
+
+    public void addDrawable(Drawable d){
+        drawables.add(d);
+    }
+
+    public boolean doesCollide(Collidable col) {
+        boolean collides = false;
+
+        for (Collidable c : collidables) {
+            double distance = Vector2D.distance(c.getCenterPos(), col.getCenterPos());
+            if (!(distance > c.getSize().magnitude() && distance > col.getSize().magnitude())) {
+                if (c.collidesWith(col)) {
+                    collides = true;
+                }
+            }
+        }
+        return collides;
     }
 }

src/main/java/core/math/Vector2D.java

@@ -157,6 +157,12 @@ public class Vector2D {
         return rotateAround(new Vector2D(), new Vector2D(0, 1), direction);
     }
 
+    public static double distance(Vector2D a, Vector2D b){
+        Vector2D dif = subtract(a, b);
+        return Math.sqrt(dif.x * dif.x + dif.y + dif.y);
+    }
+
+
     /**
      * Copy this object
      * @return A copy of this object

src/main/java/core/physics/Collidable.java

@@ -1,5 +1,12 @@
 package core.physics;
 
+import core.math.Vector2D;
+
 public interface Collidable {
 
+    boolean collidesWith(Collidable o);
+    Hitbox getHitbox();
+    Vector2D getCenterPos();
+    Vector2D getSize();
+
 }

src/main/java/core/physics/Hitbox.java

@@ -1,5 +1,8 @@
 package core.physics;
 
-public abstract class Hitbox {
+import core.Drawable;
+import objects.GameObject;
+
+public abstract class Hitbox implements Drawable {
 
 }

src/main/java/core/physics/RectHitBox.java

@@ -1,4 +1,154 @@
 package core.physics;
 
+import core.Master;
+import core.math.Vector2D;
+
+import java.awt.*;
+
+/**
+ * A rectangular hitbox
+ */
 public class RectHitBox extends Hitbox {
+
+    /**
+     * The corners of the rectangle like this:
+     * <p>x1    x2</p>
+     * <p>y1    y2</p>
+     */
+    private Vector2D x1, y1, x2, y2;
+
+    /**
+     * Create a new RectHitbox with the position of the top left point {@code x1} and the size
+     *
+     * @param x1   The top left point
+     * @param size the size
+     */
+    public RectHitBox(Vector2D x1, Vector2D size) {
+        this.x1 = x1;
+        this.x2 = Vector2D.add(x1, new Vector2D(size.x, 0));
+        this.y1 = Vector2D.add(x1, new Vector2D(0, size.y));
+        this.y2 = Vector2D.add(x1, new Vector2D(size.x, size.y));
+    }
+
+    /**
+     * Move the hitbox to a new position
+     *
+     * @param x1
+     * @param size
+     */
+    public void moveTo(Vector2D x1, Vector2D size) {
+        this.x1 = x1.copy();
+        this.x2 = Vector2D.add(x1, new Vector2D(size.x, 0));
+        this.y1 = Vector2D.add(x1, new Vector2D(0, size.y));
+        this.y2 = Vector2D.add(x1, new Vector2D(size.x, size.y));
+    }
+
+    /**
+     * Check whether two hitboxes collide with each other
+     *
+     * @param o The other rectangular hitbox, should currently only be a {@link RectHitBox}
+     * @return {@code true} when they collide {@code false} when they don't
+     */
+    public boolean collidesWith(Hitbox o) {
+        if (o instanceof RectHitBox) {
+            return collidesWith((RectHitBox) o);
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * Check whether two hitboxes collide with each other
+     *
+     * @param o The other rectangular hitbox
+     * @return {@code true} when they collide {@code false} when they don't
+     */
+    public boolean collidesWith(RectHitBox o) {
+
+        //all points right of x2, left of x1, above x1, below y1 -> no collision
+
+        //if all points are right of x2
+        boolean allRight = true;
+        for (int i = 0; i < 4; i++) {
+            if (o.getPoint(i).x < x2.x) {
+                allRight = false;
+                break;
+            }
+        }
+
+        //if all points are left of x1
+        boolean allLeft = true;
+        for (int i = 0; i < 4; i++) {
+            if (o.getPoint(i).x > x1.x) {
+                allLeft = false;
+                break;
+            }
+        }
+
+        //if all points are above x1
+        boolean allAbove = true;
+        for (int i = 0; i < 4; i++) {
+            if (o.getPoint(i).y > x1.y) {
+                allAbove = false;
+                break;
+            }
+        }
+
+        //if all points are below y1
+        boolean allBelow = true;
+        for (int i = 0; i < 4; i++) {
+            if (o.getPoint(i).y < y1.y) {
+                allBelow = false;
+                break;
+            }
+        }
+
+        boolean coll = !(allAbove || allBelow || allLeft || allRight);
+        return coll;
+    }
+
+    /**
+     * Get a point like this
+     * <p>0  1</p>
+     * <p>2  3</p>
+     *
+     * @param i the point number
+     * @throws IllegalArgumentException when i is not between 0 and 3
+     */
+    public Vector2D getPoint(int i) {
+        return switch (i) {
+            case 0 -> x1;
+            case 1 -> x2;
+            case 2 -> y1;
+            case 3 -> y2;
+            default -> throw new IllegalArgumentException("i has to be between 0 and 3");
+        };
+    }
+
+    public Vector2D getX1() {
+        return x1;
+    }
+
+    public Vector2D getY1() {
+        return y1;
+    }
+
+    public Vector2D getX2() {
+        return x2;
+    }
+
+    public Vector2D getY2() {
+        return y2;
+    }
+
+    @Override
+    public String toString() {
+        return "RectHitBox{" + x1 + " " + x2 + "\n" + y1 + " " + y2 + "}";
+    }
+
+    @Override
+    public void draw(Graphics2D g2d, int w, Master master) {
+        g2d.setPaint(Color.BLUE);
+        g2d.fillRect((int) x1.y, (int) x1.y, (int) (x2.x - x1.x), (int) (y1.y - x1.y));
+    }
 }

src/main/java/objects/GameObject.java

@@ -1,7 +1,9 @@
 package objects;
 
+import core.Drawable;
 import core.Master;
 import core.math.Vector2D;
+import core.physics.Collidable;
 
 import java.awt.*;
 
@@ -9,7 +11,7 @@ import java.awt.*;
  * The GameObject class is the superclass of every GameObject that can be displayed on screen. It has the 2
  * {@link #update(Master)} and {@link #draw(Graphics2D, int, Master)} methods that have to be
  */
-public abstract class GameObject {
+public abstract class GameObject implements Drawable {
 
     protected int w;
     protected int h;
@@ -32,37 +34,36 @@ public abstract class GameObject {
         mainColor = Color.BLACK;
     }
 
-    /**
-     * <p>The draw method is called every frame after the {@link #update(Master)} by the master object on each object. Everything
-     * about drawing should be handled here in this method.</p>
-     * <p>No general calculations should be made in this method. The game should be able to work just
-     * fine even without this method being called.</p>
-     * <p>This function is <i>NOT</i> intended to be called manually.</p>
-     * @param g2d The {@code Graphics2D} object given by the master
-     * @param w The width of the screen
-     * @param master The master object itself
-     */
-    public abstract void draw(Graphics2D g2d, int w, Master master);
 
     /**
      * <p>The update method is called every frame before the {@link #draw(Graphics2D, int, Master)} method by the master object on each object. Everything
      * that is needed for the game to work should be here in this method.</p>
      * <p>No drawing should be made in this method. The {@code debug} method can be called on the master.</p>
      * <p>This function is <i>NOT</i> intended to be called manually.</p>
+     *
      * @param master The master object itself
      */
     public abstract void update(Master master);
 
     /**
      * A simple method to move the object to a Vector2D. This method should be called instead of doing it manually.
+     *
      * @param target The target position
      */
-    public void moveTo(Vector2D target){
+    public void moveTo(Vector2D target, Master master) {
+        Vector2D oldPos = position;
         this.position = target;
+
+        if (this instanceof Collidable) {
+            if (master.doesCollide((Collidable) this)) {
+                this.position = oldPos;
+            }
+        }
     }
 
     /**
      * This method draws a rectangle at the current position and size
+     *
      * @param g2d The Graphics2D object provided by the master
      * @param w   The width of the screen
      */
@@ -80,6 +81,7 @@ public abstract class GameObject {
 
     /**
      * This method draws a rounded rectangle at the current position and size
+     *
      * @param g2d  The Graphics2D object provided by the master
      * @param w    The width of the screen
      * @param arcW The arc width of the rectangle
@@ -137,4 +139,8 @@ public abstract class GameObject {
     public int getWorldCoordsFromLocalSize(double value, boolean useX) {
         return (int) getWorldCoordsSize(getMapCoordsSize(value, useX), useX);
     }
+
+    public Vector2D getCenterPosition(){
+        return new Vector2D(position.x + size.x, position.y + size.y);
+    }
 }

src/main/java/objects/ships/Submarine.java

@@ -2,14 +2,20 @@ package objects.ships;
 
 import core.Master;
 import core.math.Vector2D;
+import core.physics.Collidable;
+import core.physics.Hitbox;
+import core.physics.RectHitBox;
 import objects.GameObject;
 
 import java.awt.*;
 
-public class Submarine extends GameObject {
+public class Submarine extends GameObject implements Collidable {
+
+    private RectHitBox hitbox;
 
     public Submarine(Vector2D position, Vector2D size) {
         super(position, size);
+        this.hitbox = new RectHitBox(position, size);
     }
 
     @Override
@@ -21,6 +27,26 @@ public class Submarine extends GameObject {
     @Override
     public void update(Master master) {
         Point mouse = master.getMouseLocation();
-        moveTo(new Vector2D(mouse.x, mouse.y));
+        moveTo(new Vector2D(mouse.x, mouse.y), master);
+    }
+
+    @Override
+    public boolean collidesWith(Collidable o) {
+        return hitbox.collidesWith(o.getHitbox());
+    }
+
+    @Override
+    public Hitbox getHitbox() {
+        return hitbox;
+    }
+
+    @Override
+    public Vector2D getCenterPos() {
+        return getCenterPosition();
+    }
+
+    @Override
+    public Vector2D getSize() {
+        return size;
     }
 }

src/main/java/objects/world/Wall.java

@@ -1,14 +1,21 @@
 package objects.world;
 
 import core.Master;
+import core.math.Vector2D;
+import core.physics.Collidable;
+import core.physics.Hitbox;
+import core.physics.RectHitBox;
 import objects.GameObject;
 
 import java.awt.*;
 
-public class Wall extends GameObject {
+public class Wall extends GameObject implements Collidable {
+
+    private RectHitBox hitbox;
 
     public Wall(double x, double y, double xSize, double ySize) {
         super(x, y, xSize, ySize);
+        this.hitbox = new RectHitBox(new Vector2D(x, y), new Vector2D(xSize, ySize));
     }
 
     @Override
@@ -19,4 +26,24 @@ public class Wall extends GameObject {
     @Override
     public void update(Master master) {
     }
+
+    @Override
+    public boolean collidesWith(Collidable o) {
+        return this.hitbox.collidesWith(o.getHitbox());
+    }
+
+    @Override
+    public Hitbox getHitbox() {
+        return hitbox;
+    }
+
+    @Override
+    public Vector2D getCenterPos() {
+        return position;
+    }
+
+    @Override
+    public Vector2D getSize() {
+        return size;
+    }
 }

src/test/java/core/math/Vector2DTest.java

@@ -1,4 +1,4 @@
-package core;
+package core.math;
 
 import core.math.Vector2D;
 import org.junit.jupiter.api.Test;

src/test/java/core/physics/RectHitBoxTest.java

@@ -0,0 +1,62 @@
+package core.physics;
+
+import core.math.Vector2D;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class RectHitBoxTest {
+
+    @Test
+    void constructorSimple(){
+        RectHitBox a = new RectHitBox(new Vector2D(1, 1), new Vector2D(1, 1));
+
+        assertEquals(a.getX1(), new Vector2D(1, 1));
+        assertEquals(a.getX2(), new Vector2D(2, 1));
+        assertEquals(a.getY1(), new Vector2D(1, 2));
+        assertEquals(a.getY2(), new Vector2D(2, 2));
+    }
+
+    @Test
+    void doCollideNoCross(){
+        RectHitBox a = new RectHitBox(new Vector2D(-1, 1), new Vector2D(1, 1));
+        RectHitBox b = new RectHitBox(new Vector2D(1, 1), new Vector2D(1, 1));
+        assertFalse(a.collidesWith(b));
+    }
+
+    @Test
+    void doCollideCornerTouch(){
+        RectHitBox a = new RectHitBox(new Vector2D(0, 0), new Vector2D(1, 1));
+        RectHitBox b = new RectHitBox(new Vector2D(1, 1), new Vector2D(1, 1));
+        assertFalse(a.collidesWith(b));
+    }
+
+    @Test
+    void doCollideCornerInside(){
+        RectHitBox a = new RectHitBox(new Vector2D(0, 0), new Vector2D(2, 2));
+        RectHitBox b = new RectHitBox(new Vector2D(1, 1), new Vector2D(2, 2));
+        assertTrue(a.collidesWith(b));
+    }
+
+    @Test
+    void doCollideEdgeInside(){
+        RectHitBox a = new RectHitBox(new Vector2D(-2, 0), new Vector2D(4, 2));
+        RectHitBox b = new RectHitBox(new Vector2D(-1, 1), new Vector2D(2, 2));
+        assertTrue(a.collidesWith(b));
+    }
+
+    @Test
+    void doCollideCrossCrossing(){
+        RectHitBox a = new RectHitBox(new Vector2D(-1, 2), new Vector2D(2, 4));
+        RectHitBox b = new RectHitBox(new Vector2D(-2, 1), new Vector2D(4, 2));
+        assertTrue(a.collidesWith(b));
+    }
+
+    @Test
+    void doCollideFullyInside(){
+        RectHitBox a = new RectHitBox(new Vector2D(0, 0), new Vector2D(3, 3));
+        RectHitBox b = new RectHitBox(new Vector2D(1, 1), new Vector2D(1, 1));
+        assertTrue(a.collidesWith(b));
+    }
+
+}